Known in the art are catalysts for dimerization, oligo-merization, co- and poly-merization of ethylene and .alpha.-olefins which consist of an active phase, i.e. a transition metal compound deposited onto the surface of inorganic or organic carriers and various organo-metallic compounds.
The use of catalysts containing inorganic carriers results in an increased ash content of the polymer and, in some cases, impaired physico-mechanical properties thereof. Thus, the use of magnesium chloride (cf. U.S. Pat. No. 3,243,422; FRG (German) Pat. No. 2,033,468) as the inorganic carrier substantially impairs the dielectric constant of the resulting polymer and causes corrosion of the equipment during processing thereof.
The use of catalysts containing organic carriers is less effective due to a small specific surface area and a small total volume of pores of the carriers employed. Such catalysts possess a low specific activity (cf. French Pat. No. 1,550,186).
Also known in the art is a catalyst for polymerization of ethylene and propylene consisting of a compound of a transition metal of Groups IV-VI and VIII of the periodic system deposited onto polyolefines with a particle size of from 0.25 to 0.5 mm and a co-catalyst, viz. an organo-metallic compound (cf. FRG application No. 1,943,751).
The use of a large-size fraction of a polyolefin such as polyethylene for the catalyst preparation makes it possible to obtain large-size particles of a polymer without, however, providing for a possibility of control of the granulometric composition of the polymer obtained in the synthesis.
Other disadvantages of said catalyst reside in its rather low specific activity, a small yeld and a high ash-content of the resulting polymer.